Tamper-proof display assembly

ABSTRACT

A display assembly for posters or signs includes a cover frame having a clear sealed window at the front surface thereof. The display assembly is generally rectangular, the cover frame having four outwardly facing walls configured to slide into forwardly extending closely fitting walls extending from a one piece wall-mountable shroud-forming frame. Magnetic strips affixed to interior faces of the shroud-forming frame capture and hold an inserted cover frame, and the closely fitting shroud walls and immediately confronting cover frame walls serve to defeat the insertion of conventional tools to remove the cover when so emplaced. A special spatulate tool is configured with projections stressed to spring out of the plane of the blade in the relaxed state. The extensions are temporarily pressed flat during insertion, to spring outward when inserted to maximum depth into the assembly, the extensions when thus deployed confronting and engaging a rear portion of the cover frame. Withdrawal of the tool causes withdrawal of the cover frame for replacement of the contents.

TECHNICAL FIELD OF THE INVENTION

The technical field of the invention is the display art, and inparticular outdoor poster display sign assemblies designed to betamper-proof and weather proof.

BACKGROUND OF INVENTION

It is commonly experienced that posters or signs are frequently defaced,obliterated, or removed by vandals. Such vandalism cannot effectively beprevented simply by enclosing the poster or sign within a frame having atransparent window and fitted together by conventional fastening means,e.g. screws, since vandals frequently employ commonly available handtools such as screwdrivers to gain access to the poster or sign inside.Moreover, a problem is presented to the designer of such units in that,not only must they be tamper-proof with respect to vandals, but on theother hand it is necessary that it be a relatively simple matter foruntrained personnel to remove the old poster from the display housingand replace it with a new one.

Thus, a tamper-proof display assembly desirably should satisfy theparadoxical requirements of defeating a skilled vandal usingconventional readily available tools on the one hand, and be readilyaccessible to completely unskilled personnel for purposes of posterreplacement. Additionally, such a sign assembly should be quiteinexpensive to fabricate, and further be configured to provide adequateprotection to the display contents, e.g. a poster, against the elements,when placed in outdoor locations. Although a key-lockable pivotedtransparent door covering a sign-containing open front box-likestructure may be employed for such purposes, such assemblies are costly,and the locks are readily susceptible to freezing in cold weather.

To the applicant's knowledge, prior to the present invention asdisclosed herein, no satisfactory solution to the above mentionedproblems have been heretofore developed.

SUMMARY OF INVENTION

A weather-sealed tamper-proof display assembly designed to accepttwo-dimensional articles, e.g. posters and display signs, comprises twomajor components held to each other by preferably magnetic holding meansand separable from each other by use of a specially configured tool.These two major components in the preferred form of the inventioninclude a generally rectangular wall-mountable rear shroud-formingcomponent having forwardly extending walls forming a rectangularinsertion aperture, and a front rectangular cover frame having agenerally centrally disposed transparent viewing window sealinglyaffixed therebehind. While in accordance with the broadest aspect of theinvention the shroud could be designed to receive the display sign orposter involved, the cover frame preferably is designed to receive thesame. In the preferred form of the invention, a sign or poster-retainingmeans is affixed to the rear of the cover frame between two opposingsides thereof and preferably provides an insertion channel or pocketbehind the viewing window. Into this pocket is slid an assemblypreferably comprising a sign or poster and suitable backing sheetstherebehind, to be captively retained in position behind the window bythe retaining means. The inserted assembly preferably includes acompressible sheet shuch as polyurethane foam and a rigid backing boardto press the poster of sign flat against the window. This materiallyassists in preventing wrinkling of the poster or sign under highhumidity conditions.

Attached to the cover frame are frame holding means preferablyconfigured to present rearwardly facing surfaces to confrontcomplementary forwardly facing surfaces of holding means on theperiphery of the shroud-forming frame when the cover frame is slidinglyinserted into the insertion aperture thereof. These holding means arepreferably magnetic means. Thus, while these holding means could bespring urged holding means or Velcro (Trademark) holding means, or thelike, the use of magnetic means to be described is decidedly preferredfor cost and reliability reasons.

In accordance with another feature of the invention, weather sealingstrip means may be mounted on confronting peripheral faces of thesefront and rear display components to provide a seal against theelements.

According to a more specific aspect of the invention, one of themagnetic holding means is the ferromagnetic material of one of thecomponents, and the complementary holding means are magnetized stripspermanently bonded to the periphery of the other component so that theinserted cover frame component captively locked in the insertionaperture of the rear shroud-forming component by the magnetic force ofthe strips.

Independently of whether the holding means are on forwardly andrearwardly facing surfaces of the frame component, along at least oneside of these components is a narrow gap therebetween which permitsinsertion of a special tool to be described. The clearances between thecover frame and shroud-forming frame are so small that a conventionaltool such as a screwdriver cannot be inserted therein to pry the frameloose from the force of the holding means. This tamper-proof feature isfurther augmented by configuring the shroud walls to extend forwardlysubstantially beyond the front face of the inserted cover frame, therebyfurther inhibiting such tool access, and also providing increasedprotection against the elements. Further, to prevent theft of the entireassembly, the attachment means for mounting the shroud on a chosen wallare emplaced and affixed to interior portions of the shroud, so that anemplaced frame completely covers these means.

According to a most important further feature of the invention, thespecially configured tool of the invention is preferably a resilientmetal blade or spatula affixed to a handle, the tool preferablyappearing like a paint scraper. Arcuate cutouts provided near the distalend of the blade leave two laterally extending fingers at the end of theblade. These fingers are pre-stressed or deformed so that they projectin the same direction out of the plane of the blade. Because of theresiliency of the blade material, when the blade is inserted into thegap between the shroud and the cover frame these fingers are cammed intoa coplanar relationship with the remainder of the blade to allowinsertion deeply into the assembled structure, whereupon they spring outof this plane to confront rear portions of the cover frame. A simplepull on this tool then breaks the magnetic seal and allows the frame tobe withdrawn. The structure, because of its simplicity, is substantiallyless expensive than structures employing conventional keys and lockassemblies, and is substantially immune to low temperature freezing ofthe release mechanism.

The entire structure is most preferably fabricated from simple anglestock and sheet metal stock by welding to provide an inexpensiveweather-proof and highly tamper resistant sign or poster displayassembly characterized by minimal fabrication costs. No externalapertures, angles, or similar attachment points are presented whereby avandal using conventional tools may gain access to the poster, oralternatively remove the entire assembly from the wall.

The above and other features and advantages of the invention will becomeapparent upon making reference to the specification to follow, theclaims and the drawings.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a display frame assembly having a posterand backing sheets inserted into a channel of the frame behind a windowof a cover frame, the frame being positioned for insertion into aclosely fitting rectangular wall-mountable shroud.

FIG. 2 is a perspective view of the display frame assembly of FIG. 1captively inserted into the shroud, with the shroud mounted on a wall.

FIG. 3 is a perspective view showing an empty display frame with thetransparent cover frame mounted therein, and further showing in explodedform the poster and backing sheets to be inserted into the channel ofthe cover frame.

FIG. 4 is a front elevation of the empty cover frame of FIG. 3.

FIG. 5 is a side cross sectional view of the cover frame of FIG. 4,taken along section lines 5--5 therein.

FIG. 6 is a rear elevational view of the cover frame of FIG. 4.

FIG. 7 is a partial horizontal cross section view of the assembly shownin FIG. 2, taken along section lines 7--7 therein.

FIG. 8 is a perspective view of the assembly shown in FIG. 2 showing aspecially configured tool inserted for removal of the cover frame fromthe shroud.

FIG. 9 is a plan view of the tool of FIG. 8.

FIG. 10 is an end view of the tool of FIG. 8.

FIG. 11 is a cross section side detailed view of a portion of theinserted tool shown in FIG. 8, taken along section lines 11--11 thereofand illustrating details of the tool engagement with a rear portion ofthe inserted cover frame.

DETAILED DESCRIPTION OF THE PREFERRED FORM OF THE INVENTION

FIGS. 1 and 2 show the overall aspects of a tamper-proof displayassembly 1 adapted for mounting on a vertical wall. The two principalcomponents of the display assembly 1 are a cover frame 10 and anenclosing shroud-forming frame 12. The cover frame 10 as illustrated isformed from angle bar stock to present top, bottom and side verticalperipheral walls 10a defining a viewing opening 11 and rearwardlyexpending flanges 10b. There is sealedly affixed to the interior (rear)peripheral surfaces of the vertical walls 10a a transparent panel 16 ofa suitable material such as acrylic plastic.

Behind this window 16 are a sandwich 13 of sheets including (See FIG. 3)a two-dimensional article in the form of poster 18 or sign sheet to beviewed through the pane 16, the poster or sign sheet in turn havingemplaced therebehind a rectangular compressible sheet 20 made of asuitable material such as polyurethane foam. Behind the compressiblesheet 20 is a rigid thin rectangular backing sheet or board 22. Theposter or sign sheet 18, the compressible sheet 20 and the backing board22 are held together as a sandwich and slid into position behind thesealed-in pane 16 to be compressingly held there by a generally U-shapedchannel-forming member 14 attached by welding to the rear edges of theflanges 10b of the cover frame 10. Thus, the pocket-forming member 14has a main rear laterally extending vertical wall 14a and side flanges14b welded to the rear edges of cover frame flanges 10b. The member 14occupies only the mid-region of the cover frame and forms an accessibleupwardly facing channel opening between it and the pane 16 so that thesandwich 13 of sheets can be easily inserted into this opening. Theinitial thickness of the sheet sandwich 13 is greater than the spacingbetween wall 14a and pane 16 so that the sheet 20 is compressed toresiliently sandwich these sheets, which fit just within the confines ofthe cover frame walls 10a, between the wall 14a and the pane 16. By thismeans the poster or sign sheet 18 is pressed flat against the window.This materially assists in preventing wrinkling of the poster or signunder high humidity conditions.

A compressible sealing strip 30 is disposed along the outer faces 58 ofthe cover frame flanges 10b. A gap 32, preferably centrally located inthe sealing strip 30 at the top of the cover frame 10 is provided toallow for insertion of a specially configured tool 62 (FIGS. 9 and 10)which allows removal of the cover frame from the shroud-forming frame 12into which the cover frame is pressingly inserted.

The shroud-forming frame 12 is shown as generally rectangular frameformed from angle bar stock and presenting rear vertical walls 12a atthe top, bottom and sides thereof and forwardly projecting flanges 12bdefining within them an insertion aperture or recess 35 which fairlyclosely receives the cover frame 10. The shroud-forming frame 12 isdimensioned such that when the cover frame 10 is pressingly insertedinto the shroud-forming frame 12, the sealing strip 30 is compressedinto sealing engagement between the outwardly facing sealingstrip-carrying faces 10b to the inner faces 41 of the flanges 12b of theshroud-forming frame 12.

For reasons that will shortly become evident, in order to render theinserted cover frame 10 shown in FIG. 2 non-removable from theshroud-forming frame 12 by conventional tools, the spacing between theconfronting interior faces 41 of the peripheral flanges 10b and 12bshould be no greater than 1/16 inches. The forward-facing vertical walls12a of the shroud-forming frame 12 are provided with-four holes 29 foraccepting screws 42 passing through these walls for securing theshroud-forming frame 12 to a wall.

In addition to the frictional engagement provided by the sealing strip30 when the cover frame 10 is inserted into the closely fittingshroud-forming frame 12, there is provided a more secure cover frameholding means on the front faces of the side vertical walls 12a of theframe 12. These holding means are preferably a pair of strips 26--26 ofpermanently magnetized material. The strips are permanently affixed, asfor example by epoxy adhesive or other permanent adhering means. Whenthe cover frame 10 is inserted into the shroud-forming frame 12, therear face 50 of the pocket-forming member 14 on cover frame 10 comesinto contact with these magnetic strips 26--26 to provide a magneticattraction holding the cover frame and the shroud-forming frame securelytogether. Preferably, both the cover frame 10 and its pocket-formingmember 14 are thus made of a ferromagnetic material, such asferromagnetic type stainless steel. By this means, a strong magneticretention is secured, and the known weather proof properties of suchstainless steel may be used to maximum advantage against the elements.It will be noted with respect to FIG. 1, and more particularly withrespect to the partial section view of FIG. 7 (to be discussed) theflanges 12b of the shroud-forming frame 12 extend forwardly beyond theinserted cover frame 10 to provide an additional protection againstrain, and also to make the display assembly more tamper-proof.

FIG. 7 best shows the details of the display assembly of the invention.Here it will be seen that the planar rear face 50 of the pocket-formingmember 14 is in planar engagement with a magnetic strip 26. This stripmay be affixed as by a suitable adhesive means to the verticalperipheral wall 12a of the shroud-forming frame 12. By proper choice oflength, thickness, and magnetization of the strips 26--26, the coverframe 10 shown in FIG. 2 may be secured with sufficient anchoring forcethat it cannot be readily removed by means of ordinary tools in thehands of skilled vandals.

Further to providing a tamper-proof feature, the clear window pane 16may be permanently secured to the rear surface 52' of the peripheralvertical walls 10a of the cover frame 10 by adhesive means, such as roomtemperature vulcanizing silicone rubber, the pane 16 being thus held intight engagement with this rear surface 52' to prevent insertion of atool between the pane 16 and the rear surface 52' of a vertical wall 10aof the cover frame, thereby preventing a vandal from extracting thecover frame 16 from the shroud-forming frame 12. FIG. 7 also shows incross section the capture of a poster 18 between the pane 16 and thecompressible sheet 20 and the rigid backing board 22, this sandwichbeing held captive by the forward face 48 of the vertical wall 14a ofthe pocket-forming member 14. Thus, it is apparent that a generallyweather-tight display assembly is provided which cannot readily bevandalized because of the previously mentioned tight clearances aroundthe periphery of the cover frame 10, and because no grasping points orattachment points are provided whereby a skilled vandal having ordinarytools can quickly remove either the cover frame 10 from theshroud-forming frame 12, or alternatively the poster 18 from the coverframe.

FIGS. 9 and 10 show views of a frame removal tool 62 designed forinsertion as shown in FIG. 8 through the gap 32 in the sealing strip 30between the upper face 58 of the cover frame 10 and the confrontinginterior surface 34' of the top flange 12b of shroud-forming frame 12.In the preferred form of the invention, the tool 62 is fabricated bymodifying a spatula paint scraper having a handle 68 and a blade 64 ofhighly flexible material. This spatula tool 62 is configured with a pairof inwardly extending cut-outs 65 proximate to the distal end of theblade 64 and locally reducing the span of the blade 64 immediatelyproximate to the end thereof. The remaining outwardly extending portionsor extensions 70 of the blade 64 are further configured with leadingshoulders 72 extending from leading points 73 approximately opposite themaximum inward encroachment of the cut-outs 65 to sweep back moderatelyto the ends of the extensions 70. Further, the extensions 70 are bent inthe same direction and out of the general plane of the blade 64 as shownin FIG. 10. These extensions are thus flexible members having generallytransversely extending rearwardly facing shoulders 75 disposed in theirrelaxed state out of the general plane of the blade 64.

As shown in FIG. 8, such a tool may readily be inserted between theupper face 58 of the cover frame 10 and the confronting surface 34' ofthe upper horizontal wall 12b. The cover frame 10 is here shown slightlywithdrawn from the shroud-forming frame 12. FIG. 11 shows a crosssection partial detail view of the tool so inserted. It will be notedthat when the blade 64 is inserted as shown, the extensions 70automatically encounter an unobstructed region wherein they can springout of the common plane of the blade 64 to reside in an extendedposition behind the rearmost portion of the upper flange 12b of thecover frame 12. This unobstructed region arises from the fact that theposter 18, the compressible sheet 20, and the backing board 22 areconfigured slightly undersize with respect to the general confines ofthe cover frame 10 so that the upper ends thereof lie slightly below therearmost portion 49 of the upper flange 10b of the cover frame 10. Thus,an inserted tool of the type described herein may be inserted to engagethe rearmost portion 49 of the cover frame 10 at the top thereof. Anoutward pulling force thereafter applied to the handle 68 of the tool 62can apply sufficient force to break the securing magnetic attractionbetween the magnetic strips 26 and the rear face 50 of thepocket-forming member 14, extracting the frame as indicated by thedotted lines in FIG. 11.

It will be noted that, because of the rather substantial force necessaryto break the magnetic bond, and because of the closely fittingrelationship between the confronting portions of the cover frame 10 andshroud-forming frame 12, the employment of conventional tools, short ofactually cutting into portions of the assembly, is not likely to besuccessful in removing the cover frame 10. Thus, an inserted screwdriverblade employed by a vandal and forced between the outer margins of thecover frame 10 and the inner margins of the shroud-forming frame 12, andwhich is thin enough to fully enter the passage therebetween would notbe strong enough to eject the frame by an upward prying movement.Conversely, a screwdriver massive enough to supply such a force would betoo thick to secure adequate depth of entry. Since in the preferred formof the invention, as previously mentioned, the pane 16 is permanentlysecured in place, a prying or hooking engagement of any conventionaltool with the front of the cover frame 10 or its associated frontalmargins is similarly precluded.

On the other hand, no mechanical skill whatever is necessary to thepossessor of the tool 62, which by a simple insertion and withdrawalaction readily removes the cover frame 10. It is further to be notedthat the mounting screws 42 holding the shroud-forming frame 12 to itschosen supporting wall are inaccessible to the vandal, since they arecompletely covered by a cover frame 10. Also, since all elements of thestructure are secured by a permanent means such as welding, there are noconvenient externally accessible screws providing a vandal with a meansto remove a portion of the assembly to obtain access thereinto. It willfurther be noted that there is no requirement whatever for complexmechanical linkages, e.g. key-actuated locks, to secure the tamper-prooffeature, resulting in a structure that is characterized by a lowmanufacturing cost and reliability of operation, while further providingan adequate degree of protection of the interior of the display frameassembly 10 against the elements.

While the invention has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to a particular embodiment disclosed as the best modecontemplated for carrying out the invention, but that the invention willinclude all embodiments falling within the scope of the appended claims.

Thus, for example, the central concepts of the present invention are notnecessarily restricted to a rectangular structure. It is quite clearthat the shroud-forming frame and cover frame could be configured withmatching arcuate surfaces, the only requirement being that the insertionpoint for the tool must be located at a point where the radius of anysuch arc is sufficiently great that the tool can be inserted withoutcausing permanent deformation thereof.

Additionally, alternative forms of holding means may be employed to holdthe cover frame in the shroud. These may, for example, take the form ofspring-loaded balls on one unit and matching detents on the other.Alternatively confrontingly opposed strips of locking-bristle fabricsuch a Velcro (Trademark) may be employed. All that is required is thatthe holding means be adequately strong to resist conventional pryingtools, and be substantially immune to erratic operation in freezingweather.

We claim:
 1. A display assembly for accepting a sign or poster sheet orthe like for the display thereof comprising:a shroud-forming frameincluding attachment means for attaching said shroud-forming frame to avertical mounting surface, said shroud-forming frame having peripheralwalls forwardly extending from forwardly facing vertical surfacesinterior to said peripheral walls, said peripheral walls defining aninsertion aperture into said shroud-forming frame from the frontthereof; a cover frame having peripheral margins presenting outwardlyfacing surfaces configured for closely confronting nesting relationshipwith the interior surfaces of said peripheral walls of saidshroud-forming upon insertion of said cover frame into said insertionaperture, said cover frame having rearwardly facing vertical surfacesand a sealed transparent forwardly facing viewing portion forming awindow through which a sign or poster sheet behind the same is visible;retaining means for accepting and holding a poster or sign sheet behindsaid window; one of said cover frame and said shroud-forming frameincluding a first holding means, the other of same including secondholding means releasably engaging said first holding means, said firstand second holding means being disposed within said assembly to providea force operating to hold said cover frame in said shroud-forming framewhen inserted therein so that said shroud-forming frame completelysurrounds the sides of said inserted cover frame to prevent directaccess to the rear surfaces of said cover frame, said cover frame andshroud-forming frame being configured to provide a first tool-receivingforwardly opening narrow gap between the confronting portions of saidoutwardly facing surfaces of said cover frame and said interior surfacesof said peripheral walls of said shroud-forming frame.
 2. The displayassembly of claim 1 wherein said retaining means is part of said coverframe.
 3. The display assembly of claim 1 wherein said holding means onsaid shroud-forming frame is disposed on on one or more of saidforwardly facing vertical surfaces thereof and said holding means onsaid cover frame is disposed on one or more of said rearwardly facingvertical surfaces thereof.
 4. The display assembly of claim 1 whereinsaid cover frame is provided with at least one rearwardly facing surfaceimmediately adjacent at least one of said outwardly facing surfacesthereof and disposed at a standoff distance from said forwardly facingvertical surfaces of said shroud-forming frame with said cover frameinserted so as to provide engaging surfaces in an unobstructed regionfor engagement with one or more deployable blades of a generally planarcover frame extraction tool configured to enteringly pass through saidfirst narrow gap, and further combined with said extraction tool, saidtool comprising:a handle at the proximal end of said tool; and aresilient blade affixed to said handle and configured with at least onespringingly deformable portion at the distal end thereof, saiddeformable portion being urgeable by insertion of said tool into saidgap into a generally coplanar relationship with the remainder of saidblade and springing out of said relationship when within said standoffdistance and confrontingly to engage at least one of said rearwardlyfacing faces of said cover frame for withdrawal of said cover frame forsaid shroud-forming frame.
 5. The display assembly of claim 1 combinedwith a tool comprising: a handle at the proximal end of said tool, aresilient blade affixed to said handle and configured with at least onespringingly deformable portion at the distal end thereof, saiddeformable portion being urgeable by insertion of said tool into saidgap into a generally coplanar relationship with the remainder of saidblade and springing out of said relationship to deploy and engage aperipheral side of said cover frame for withdrawal of said cover framefrom said shroud-forming frame, and said assembly provides anunobstructed region immediately behind the portion of said peripheralwall of said cover frame to be engaged, and said at least one deformableportion of said tool is configured to present when deployed afterinsertion an outwardly facing shoulder confronting the interior end ofsaid peripheral wall.
 6. The display assembly of claim 1 wherein thereis further provided compressible weather-sealing means disposed alongsaid outwardly facing surfaces of said cover frame for resilientlyengaging said interior surfaces of said peripheral walls of saidshroud-forming frame.
 7. The display assembly of claim 6 wherein asecond tool-receiving gap is formed in said weather-sealing means toallow insertion of said tool.
 8. The display assembly of claim 7combined with said tool.
 9. The combination of claim 4, 5, or 8 whereinsaid blade is configured as a spatula having a generally increasingbreadth towards the distal end thereof, and a pair of said deformableportions are formed by providing inwardly extending cutouts in saidblade proximate to a transversely disposed generally linear distal bladeend.
 10. The display assembly of claim 7 wherein said secondtool-receiving gap extends along only a limited portion one side of theconfronting peripheral walls of said frames.
 11. The display assembly ofclaim 1 wherein said attachment means includes fastening means forfastening said shroud-forming frame to said vertical surface andaccessible only when said cover frame is removed.
 12. The displayassembly of claim 11 wherein said shroud-forming frame includesgenerally vertical planar backing walls extending transversely from therear of said forwardly extending peripheral walls to define the rear ofsaid insertion aperture, and said fastening means includes at least onefastener-accepting hole passing through one of said forwardly facingvertical surfaces of said shroud-forming frame and accessible from thefront of said shroud-forming frame only through said insertion aperture.13. The display assembly of claim 1 wherein said forwardly extendingperipheral shroud forming forward walls are configured to extend forwardbeyond the margins of said cover frame when fully inserted therein. 14.The display assembly of claim 1 wherein said forwardly extendingperipheral walls of said shroud-forming frame form a rectangularinsertion aperture and said cover frame is generally rectangular havingoutwardly facing peripheral margins closely fitting into said insertionaperture.
 15. The display assembly of claim 1 wherein said sealedtransparent portion of said cover frame is a planar sheet permanentlysecured to the margins of an aperture in said cover frame.
 16. Thedisplay assembly of claim 15 wherein said retaining means includes aretaining member secured to the rear of said cover frame at a standoffdistance from and parallel to the rear face of said transparent sheet toprovide therebetween space for insertingly accepting a display poster orsign therebetween.
 17. The display assembly of claim 16 wherein saiddisplay assembly further includes a compliant compressible sheetconfigured for sliding insertion along with a poster into said space tobe compressingly frictionally retained as a sandwich therein by saidretaining means.
 18. The display assembly of claim 1 wherein said firstholding means and said second holding means include at least a pair offerromagnetic members, at least one of which is permanently magnetized.19. The display assembly of claim 18 wherein said holding means on oneof said frames includes at least one magnetized strip disposed on one ormore vertical surfaces thereof and said holding means on the other ofsame includes at least one magnetizable surface on the latter frame anddisposed to face and contactingly engage said at least one magnetizedstrip.
 20. The display assembly of claim 19 wherein said sealedtransparent portion of said cover frame is a planar sheet permanentlysecured to the margins of an aperture in said cover frame and saidretaining means includes a planar retaining member secured to the rearof said cover frame at a standoff distance from and parallel to the rearface of said transparent pane to provide therebetween space forinsertingly accepting a display poster or sign therebetween, and said atleast one magnetized strip is disposed on said forwardly facing verticalsurface of said shroud-forming frame to confrontingly contact the rearsurface of said retaining member when said cover frame is inserted intosaid shroud-forming frame, and wherein at least said retaining member ismade of ferromagnetic material.
 21. A frame removal tool for a displaysign assembly, said assembly including a cover frame and ashroud-forming frame having means for mounting said shroud-forming frameon a vertical surface, said shroud-forming frame including attachmentmeans for attaching said shroud-forming frame to a vertical surface andhaving forwardly extending peripheral walls defining an insertionaperture into said shroud-forming frame from the front thereof, saidcover frame having peripheral margins presenting outwardly facingsurfaces configured for closely confronting nesting relationship withthe interior surfaces of said peripheral walls of said shroud-formingframe upon insertion of said cover frame having a forwardly facingviewing and sealing window through which a sign or poster sheet behindthe same is visible, said display assembly including holding meansdisposed within said assembly to provide a force operating to hold saidcover frame in said shroud-forming frame when inserted therein, saidshroud-forming frame completely and closely surrounding the sides ofsaid inserted cover frame so that said shroud-forming frame completelysurrounds the sides of said inserted cover frame to prevent directaccess to the rear surfaces of said cover frame, said cover frame andshroud-forming frame being configured to provide a forwardly openingnarrow gap between a portion of the interior surface of one of saidshroud walls, and the confronting peripheral surface of said frame, saidtool comprising:a handle at the proximal end of said tool; and aspatulate resilient blade affixed to said handle and configured with atleast one springingly deformable portion at the distal end thereof, saiddeformable portion being urgeable by insertion of said tool into saidgap into a generally coplanar relationship with the remainder of saidblade and springing out of said relationship to deploy and engage aperipheral side of said frame for withdrawal of said frame from saidshroud.
 22. The frame removal tool of claim 21 wherein there is providedin said assembly an unobstructed region immediately behind saidperipheral side member to be engaged, and said at least one deformableportion of said tool is configured to present when deployed afterinsertion a forwardly facing shoulder confronting the interior end ofsaid peripheral side.
 23. The frame removal tool of claim 22 whereinsaid blade is configured as a spatula having a generally increasingbreadth towards the distal end thereof, and a pair of said deformableportions are formed by providing inwardly extending cutouts in saidblade proximate to a transversely disposed generally linear distal bladeend.
 24. The frame removal tool of claims 21, 22, or 23 and wherein saidattachment means are disposed to be inaccessibly covered by an insertedcover frame.